The present invention relates to an optical assembly comprising a conical mirror.
US 2012/0275043 discloses a known optical assembly comprising a conical mirror, a collimation lens, an optics carrier comprising a first carrier element to which the collimation lens is attached and a second carrier element to which the conical mirror is attached, and a connection device, which connects the first and second carrier elements to each other. The optical assembly is arranged in the beam path of the laser beam behind a laser beam source. The laser beam source generates a diverging laser beam, which strikes the collimation lens and leaves the collimation lens as a collimated laser beam. The conical mirror has a reflecting exterior surface, which deflects the collimated laser beam and forms it into an annular beam, which propagates out in a propagation plane perpendicular to the conical axis of the conical mirror.
The connection device, which connects the first and second carrier elements to each other, comprises three or more thin-walled connection elements, which connect the carrier elements to each other. In doing so, the thin-walled connection elements are arranged parallel to the conical axis of the conical mirror and the lines (“extension lines”) intersect on the conical axis. The perpendicular orientation of the thin-walled connection elements has the disadvantage that the annular beam is fully interrupted in the region of the connection elements and interruptions occur in the annular beam when projecting the annular beam on to a substrate. The width of the interruption increases as the distance to the conical mirror increases.
The object of the present invention is to further develop an optical assembly having a conical mirror so as to avoid interruptions in the annular beam during the projection onto a substrate.
According to the invention, it is provided that at least one connection element is arranged askew to the conical axis of the conical mirror. Two lines are described as being askew when they do not intersect nor are they arranged parallel to each other.
The skewed arrangement of the connecting element to the conical axis of the conical mirror has the advantage that a portion of the annular beam can propagate above the connection element and a portion of the annular beam can propagate below the connection element; only the portion of the annular beam which strikes the connection element directly is blocked out. The blocked-out portion of the annular beam can result in the brightness of the annular beam being reduced in this angle range, wherein this reduction can hardly be perceived by the user. The width of the angle range in which the brightness of the annular beam is reduced can be adjusted via the tilt angle of the connection element; the greater the inclination at which the connection element is arranged, the broader the angle range having the reduced brightness.
In a development, the connection device has a number of 2n, n≥1 connection elements, wherein n connection elements are designed as descending connection elements and n connection elements are designed as ascending connection elements, and the descending and ascending connection elements are arranged in a peripheral direction of the conical mirror in an alternating sequential manner. The oppositely oriented arrangement of the connection elements improves the stability of the connection between the carrier elements.
Preferably, the first carrier element, the second carrier element, and the connection device are designed in an integral manner. The integral design of the optics carrier and the connection device has the advantage that the adjustment of the carrier elements already occurs when manufacturing the one-piece optics carrier.
In a particularly preferred manner, the first carrier element, the second carrier element and the connection device are designed as an integral die-cast part. The design as a die-cast part has the advantage that complex shapes can also be executed for the connection elements.
Preferably, the connection elements are designed in a helical shape. The helically shaped design of the connection elements allows one to further reduce the portion of the annular beam which is blocked out by the connection elements, compared to flat connection elements. Due to the inclining of the connection elements, a connection element is struck by various parts of the annular beam. The helically shaped design of the connection elements results in each part of the annular beam, which propagates radially out from the reflecting exterior surface of the conical mirror, striking the connection element in a perpendicular manner and the blocked-out portion of the annular ring being minimized.
In a preferred embodiment, the at least one connection element is inclined by an inclination angle of between 5° and 45° to the conical axis. One can adjust the width of the angle range, in which the brightness of the annular beam is reduced, via the inclination angle of the connection elements to the conical axis. The greater the inclination at which the connection elements are arranged, the broader the angle range having the reduced brightness.
Preferably, the at least one connection element in the propagation plane has a distance to the conical axis of between 5 mm and 20 mm. A distance between 5 mm and 20 mm to the conical axis allows for a compact design of the optical assembly.
In a preferred embodiment, the connection device has a number of at least 3 connection elements, wherein the thickness of the connection elements is between 0.1 mm and 0.7 mm. To ensure sufficient stability of the connection device, one connection element can be used, which must be designed to be correspondingly thick. Alternatively, multiple thin-walled connection elements with wall thicknesses between 0.1 mm and 0.7 mm can offer sufficient stability.
Embodiments of the invention are described below by means of the drawings. It is intended to show the embodiments not necessarily to scale; rather, the drawings, where useful for explanation purposes, are executed in a schematic and/or slightly distorted manner. Regarding amendments to the teachings directly evident from the drawings, one shall refer to the relevant prior art. In doing so, one shall take into account that diverse modifications and changes pertaining to the form and detail of an embodiment can be undertaken without departing from the general idea of the invention. The features of the invention disclosed in the description, drawings and claims may be essential both individually on their own as well as in any combination for the further development of the invention.
Also falling within the scope of the invention are all combinations of at least two of the features disclosed in the description, drawings and/or claims. The general idea of the invention is not restricted to the exact form or detail of the preferred embodiments depicted and described hereafter, or limited to a subject matter that would be restricted in comparison to the subject matter claimed in the claims. For given measurement ranges, values lying within the mentioned limits shall also be disclosed as limit values and one shall be able to use and claim these as one wishes. For the sake of simplicity, the same reference signs are used for identical or similar parts, or parts with an identical or similar function.